Flow directing centrifugal contacting apparatus with jet mixing action



N0V 15, 1966 w. J. PODBIELNIAK ETAL 3,2558

FLOW DIRECTING CENTRIFUGAL CONTACTING APPARATUS WITH JET MIXING ACTIONFiled Aug. 22, 1965 2 Sheets-Sheet 1 fab jow NOW-15, 1966 w. J.PODBIELNIAK ETAL 3925,50@

FLOW DIREGTING CENTRIFUGAL CONTACTING n APPARATUS WITH JET MIXING ACTIONFlled Aug. 22, 1963 2 Sheets-Shree?l 2 j2me Si JO? Joa@ United StatesPatent O 3 285,508 FLQW DIRECTING CNTRIFUGAL CNTACTING APPARATUS WliTHJET MIXING ACTIN Walter l. Podbielniak, Chicago, and William D. Kohlns,Gien Ellyn, Ill., assignors to Dresser Industries, Inc., Dalias, Tex., acorporation of Delaware Fiied Aug. 22, 1963, Ser. No. 303,792 Claims.(Cl. 233-15) This invention `relates to a flow directing centrifugalcontacting apparatus which also provides a jet-type mixing action. Moreparticularly, the invention is concerned with an apparatus 4forcontacting two at least partially immiscible phases of differentdensities. The apparatus of the kind with which the present inventioncan be utilized has a rotor adapted for rotation about a horizontalaxis, which rotor provides a cylindrical chamber extending radiallyoutward from the axis. The radially innermost and outermost portions ofthis chamber provide resepctively light and heavy phase clarifying zonesand the intermediate portion of the chamber provides a contacting zone.Devices of the kind with which this invention is concerned are describedin United States Patents 2,75 8,- 783 and 2,758,784.

As illustrated by the .patents just cited, it lhas been the practice toemploy perforated rings within the contacting section of the rotor. Therings are 'usually concentrically arranged in radially spaced relationso that the phases must pass through the ring perforations in movinginwardly yand outwardly through the annular passageways providedybetween the rings. The predominent flow within the contacting sectionis `therefore counte-rcurrent with the heavy phase moving outwardlythrough the perforations and the light phase moving inwardly throughIthe same perforations. With this arrangement, the Iphases distri-butethemselves relatively uniformly throughout the contacting section of therotor, but the stage efficiency achieved 'is yfar below that whichshould be theoretically possible. No particular flow direction isimposed on the phases within the annular passageways.

Some attempts have heretofore been Imade to impose a more definite -owpattern on the phases within the contacting section of the rotor. Forexample, prior Patent 2,758,783 describes contacting rings having offsetsectional `perforated areas. Such a design is of value in preventing atendency of either or both phases to channel through the contactingsection without being repeatedly mixed and separated.

In prior Patent 2,840,301 a centrifugal cc-untercu-rrent contactingapparatus is described employing contacting rings which are providedwith axially and circumferentially distributed perforations, and alsowith nozzleequipped orifices or larger cross-sectional area than theperforations. With this construction, depending on t-he radial directionin which the nozzles extend, the light or heavy phase, as the case maybe, tends to flow predominately through the orifices, while the otherphase flows predominatingly through the ring perforations. In operation,as with other ring-equipped centrifugal contacting devices, the mixingand separation of the phases occurs within the ring passageways, but theflow of the phases is not controlled to the extent that there aredefinite mixing and separating areas within the passageways.

Redlich Pat-ent 2,169,280 describes a centrifugal contactor and methodof contacting wherein 'an effort is made to hol-d one of the phases inquiet zones of substantial radial depth along the inside or outsidewalls of the perforated rings. According to the disclosure of thispatent, the other phase is made to ow axially across these quiet zones,the axially `flowing phase is brought into contact with disperseddroplets of the phase which passes from the quiet zones through the ringperforations into the 3,285,588 Patente-d Nov. 15, 1966 ice flowingstream. In this type o-f design therefore it is propose-d to provide amixing zone adjacent one wall of the rings and a clarification orseparating zone against the other wall of the rings. ln other words, theinterring mixing Iand clarification areas extend across the full axiallength of the rotor. In practice, however, the use of close band spacingand the existence of rotational swirl impose-d on the -ph-ases by thehigh rotational speed of the rotor, would tend to make it extremelydifficult to establish and maintain such a flow pattern.

It is therefore a general object of this invention to provide acentrifugal contacting apparat-us and more particularly to provide, flowdirecting means within the contacting section of the rotor which imposes.a substantial degree of control on the flow of both of the phasesthrough the contacting zone. More specifically, it is an object toprovide an apparatus of t-he character described which establishes andmaintains definite mixing and contacting areas within the inter-ringypassagew-ays. Still another object is to achieve the indicated resultsby ernploying contacting rings or elements of special design whichprovide sequential mixing and separating areas between the contactingelements even though the contacting elements or rings are closely spacedwhen the apparatus is operated at high rotational speeds. Morespecifically, it is an object of this invention to employ means withradially spaced contacting rings which provide a flow pattern withineach of the annular passageways between the rings whereby the phases areintermixed i-n one area, passed cocurrently to another area, andseparated as they pass respectively inwardly or outwardly to the nextadjacent annular passageway. Still another object is to provide incombination with such apparatus, means for achieving a substantiallyjet-type mixing of the phases as they enter the `annular passageways.Further objects and advantages will be indicated in the 'following`detailed specification.

The invention is illustrated in several embodiments thereof in theaccompanying drawing, in which- FIGURE 1 is a side sectional view of avportion of a centrifugal rotor embodying features of the presentinvention;

FIGURE 2 is a fragmentary sectional end view of two of the contactingrings of the apparatus of FIG. l, taken on line 2 2 of that figure;

FIGURE 3 is a side sectional view of a Iportion of a lcentrifugal rotorembodying a modified form of the present invention;

FIGURE 4 is a fragmentary sectional view of the interior of the rotor ofFIG. 3, taken on line 4 4 thereof; showing particularly the heavy phaseremoval means;

FIGURE 5 is a fragmentary sectional view of one of the center portionsof two adjacent contacting elements in the ro-tor of FIG. 3.

Looking first at FIG. 1 of the drawings, there is shown a portion of acentrifugal contacting apparatus having a rotor 10 adapted for rotationabout a horizontallyextending shaft'll. Rotor 10 is formed from sideplates 10a and 10b and an outer cylindrical plate 10c. The generalconstruction and operation of such centrifugal rotors is described inprior Patents 2,758,783 and 3,053,440. As is well-known in the art,means is provided for driving the shaft l1 at controlled rotationalspeed, the shaft being mounted on suitable bearings, and means is alsoprovided for introducing and removing liquids from the passages withinthe shaft.

As can be seen by the further consideration of FIG. l, rotor 10 providesa cylindrical chamber 12 therein which extends radially outward fromshaft 11. The shaft includes an internal passage 13 for supplying thelight phase to the rotor chamber through radially extending tubes 14.Shaft 11 also provides a passage 15 for supplying the heavier phasethrough radially extending tubes 16. The lighter phase is removed from aposition adjacent shaft 11 through lateral passages 17 which connectwith shaft passage 18. The passage for removal of the heavy phase isprovided by spill-over disc 19 and end wall 10a, the passage beingdesignated by the number 20, and this passage connecting with shaftpassage 21, It will be noted that the light phase is introduced tochamber 12 at a position considerably further out in the rotor chamberthan the position at which the heavy phase is introduced, the regionbetween the points of introduction of the light and heavy phasescomprising the principal extracting flow area or contacting zone. Also,it will be noted that the heavy phase is removed from a positionsubstantially further out than the point of introduction of the lightphase, the region therebetween comprising the principal heavy phaseclarification section. Similarly, the light phase is removed from aposition considerably closer to the shaft than the point of introductionof the heavy phase, the region therebetween comprising the principalclarification section for the light phase. Within the contacting sectionof rotor 12 there is provided a group of rings disposed in radiallyspaced relation, which provide a plurality of generally annularaxially-extending passageways therebetween. Preferably, as shown, thesepassageways are circumferentially and axially open and unobstructed toliquid flow. In the illustration given in FIG. l, the contacting ringsinclude alternately positioned rings 22 and 23, the rings beingsubstantially identical in construction except for the respective leftand right hand reversal within the rotor chamber. FIG. 1 illustrates apreferred embodiment of the present invention wherein the rings 22 and23 have a frusto-conical shape. As will be noted, rings 22 and 23provide walls which are inclined at a small acute angle with respect tothe horizontal on a vertical plane or section including the axis of therotor, such as the section of FIG. l. In accordance with the presentinvention, walls 22 and 23 are arranged in an alternating pattern withinthe contacting section of the rotor. For example, in the illustrationgiven, the rings 22 provide walls which converge toward the right handend or side of the rotor, while the rings 23 provide walls whichconverge towards the left hand side of the rotor. It is preferred tohave the rings 22 and 23 extend entirely across the length of the rotorspace, as shown.

In accordance with the present invention each of the contacting rings,such as the rings 22 and 2.3, are provided with at least two perforatedplate sections for radial phase ow. The rings 22 have perforated platesections 22a and 22h, while the rings 23 have corresponding perforatedplate sections 23a and 23h. These perforated sections are respectivelyseparated by relatively imperforate areas of the rings, which in theillustration given are designated respectively by the numbers 22C and23C. Plate sections 22a and 23a are for the flow of the heavier phase tothe next outer one of the annular passageways. Plate sections 22b and23h are for the flow of the lighter phase to the next inner one of thepassageways. As will be noted, each of the plate sections 22a, 22h, 23aand 23b are provided with a plurality of small perforations which extendacross the axial width of the sections. It will be understod that theperforations in these sections also extend circumferentially around therings. In embodiments like that of FIG. l, it is preferred to have theperforated plate sections located in the axially outer portions of therings adjacent the sides a and 10b.

In accordance with the present invention, plate sections 22a and ZZb arepositioned respectively in radially opposed relation to plate sections23b and 23a for adjacent rings. This arrangement provides at least twopairs of opposed plate sections for each of the annular passagewaysbetween the rings. As will be noted, the imperforate areas 22a` and 23eare also in radially opposed relation. In the operation of the device ofthe present invention, one of the pairs of plate sections serves asphase entrance ports for the passageways and the other pair It will beunderstood that a particular plate section on one side will serve as anentrance port for the annular passageway on that side, while serving asan exit port for the annular passageway on the other side. For example,as shown in FIG. 1, the plate sections 22b and 23a serve as entranceports for the outermost annular passageway of the contacting sectiondesignated by the letter a, while the plate sections 23a and 22b serveas exit ports for the next innermost annular passageway designated bythe letter b. Similarly, the exit ports for the passageway a areprovided by the plate sections 22a and 23h, and the entrance ports forthe passageway b are provided by the plate sections 23b and 22a.

In achieving the benefits of the present invention, such as directedphase flow and jet-type mixing action, it is important that theperforated plate sections within each of the rings be located atdifferent radial distances from the axis of the rotor. For example, inthe embodiment of FIG. l the plate sections 22a and 23a are located atgreater radial distances from the axis of the rotor than theirrespective sections 2211 and 23b. In other words, there should be adefinite change in radial ow position or level between the perforatedplate sections of each ring. The relationship can also be stated interms of the radial spacing of the pairs of plate sections for eachannular passageway. More specifically, the plate sections providing theentrance ports should be more closely spaced than the plate sectionsproviding the exit ports. With this construction, the phases are forcedthrough the entrance ports with each of the phases being brokenup intone streams or jets which meet head-on within the confined space betweenthe entrance ports, thereby achieving thorough intermixing and mutualdispersion of the phases. The phases are then passed co-currentlythrough the portions of the passageways between the imperforate areas,such as the areas 22a` and 23C, and separated in the portions of thepassageways between the exit ports. With the frusto-conical rings of theembodiment of FIG. 1, the separation and clarification of the phases ispromoted by the movement of the phases along the inclined walls into anenlarging portion of the rotor passageway.

In FIG. l, the ow of the phases through the rotor and the contactingsection thereof is indicated by the llow arrows, some of which arefurther identified with a H or an L enclosed within a circle, whichindicates respectively the heavy or the light phase. In operatingdevices constructed in accordance with the present invention, it ispreferred that the perforated plate sections which function as exitports from a particular passageway should have a layer of the separatedphase maintained thereon so that the perforations pass only the desiredphase to the next annular passageway while largely excluding any flow inthe opposite direction through the same perforations of the opposingphase. For example, as shown in FIG. l, the heavy phase enters throughthe tube 16 and flows along the inner surface of the innermost ring 23toward the plate section 23a. As indicated in FIG. l, a layer of theheavy phase H is maintained on the inside surface of the plate section23a. Similarly, the light phase is introduced through the tubes 14outside of the outermost ring 22, passing along the outside surface ofthe ring to form a layer L on the outside surface of plate section 22b.Within the annular ring passageways, such as the passageway a, layers ofthe heavy phase H and the light phase L are maintained over the insidesurfaces of the exit plate sections. It Will be understood that thedrawing shows these phase layers somewhat diagrammatically, and that theexact boundaries of the phase layers need not be as illustrated.

A modified embodiment of the present invention is illustrated in FIGS. 3to 5. Looking first at FIG. 3, there is shown a centrifugalcountercurrent contacting apparatus having a rotor adapted for rotationabout a horizontal axis, the rotor being rigidly mounted on ahorizontallyextending shaft 101. Rotor 100 is formed from side plates100:1 and 100i and an outer cylindrical plate 100m serves as phase exitports.

The general construction and operation of rotor 100 is similar to therotor of FIG. 1.

Rotor 100 provides a cylindrical chamber 102 which extends radiallyoutwardly from shaft 101. The shaft includes an internal passage 103 forsupplying the light phase to the rotor chamber through radiallyextending tubes 104. Shaft 101 also provides a passage 105 for supplyingthe heavier phase through radially extending tubes 106. The lighterphase is removed from a position adjacent shaft 101 through lateralpassages 107 which connect with shaft passage 108. The heavy phase isremoved through a tubular return 120 which communicates with a shaftpassage 121. The inlets to tubular return 120 are designed as 12011.

Within the contacting section of rotor 12 there is provided a group ofrings disposed in radially spaced relation. In the illustration given,the contacting rings include alternately positioned rings 122 and 123,the rings being formed of two frusto-conical members, which are unitedat their centers by welding, as indicated more clearly in FIG. 5. Aswill be noted, the walls of adjacent rings alternate with respect totheir convergence and divergence toward the center and sides of therotor. This arrangement adapts the basic construction of the contactingelements of FIG. 1 for extended rotors, that is, for rotors which have arelatively long axial extent. For example, this design would be welladapted for rotors having axial widths of from 40 to 60 inches. As withthe embodiment of FIG. 1, the walls provided by rings 122 and 123, haveportions which are inclined at acute angles with respect to thehorizontal at the inner sections of the wall portions with a verticalplane through the axis of the rotor.

The rings 122 and 123 respectively provide three perforated platesections for radial phase flow, these sections in the rings 122 beingdesignated as 12211, 122C, and 122e, and the corresponding sections inthe rings 123 being designated as 123a, 123C, and 123e. As with theembodiment of FIG. 1, the perforated plate sections are separated byrelatively imperforate areas of the rings, which in the illustrationgiven are designated by the numbers 122b and 122d for the rings 122, andby the num- 123b and 123d for the rings 123. The phase ow through theperforated sections, and through the passages between the rings isindicated by arrows in FIG. 3. Speaking generally, where the perforatedplate sections are relatively close together, the phases flow towardseach other and are intermixed, while where the perforated plate sectionsare relatively far apart, `the phases ow away from each other as theyare separated. As will be noted, the intermixing of the phases and theseparation of the phases alternately occurs at the center of the rotorand adjacent the sides thereof. For example, with respect to theoutermost ring 122 and the next innermost ring 123, the phases areintermixed adjacent the sides of the rotor, ow inwardly toward thecenter, and are separated, passing outwardly and inwardly respectivelythrough the plate sections 122C and 123C. With respect to the spaceprovided between the next inward ring 122 and the outermost ring 123,the intermixing of the phases occurs at the center, and the phases thenow outwardly concurrently in both directions, and are separated adjacentthe perforated sections 123g, 12251, and 123e, and 122e. Thisalternating flow pattern is then repeated sequentially as the phases owinwardly and outwardly through the contacting section of the rotor.

The embodiment of FIG. 3, also includes perforated rings in the lightand heavy clarifying zones of the rotor. In the illustration given, theheavy phase clarifying Zone includes perforated rings 125 and apartially perforated ring 125. Similarly, the light phase clarifyingZone includes perforated rings 124 and a partially perforated ring 124'.The construction of the partially perforated ring 125 is shown moreclearly in FIG. 4. The ring includes an imperforate area 125:1immediately surrounding the pickup inlets 12.81 for the removal of theheavy phase vrings 25. Rings 25 through the tubular return 120. Thisconstruction provides for more uniform pickup of the heavy phase acrossthe full width of the rotor, and prevents any tendency of the heavyphase to channel through the central portion of the heavy phaseclarifying zone. The use of a specially designed pickup ring, such asthe ring 125 immediately radially inward of the heavy phase outlets isespecially desirable in relatively wide rotors, that is, rotors whichhave an axial extent of 40 inches or more. However, it can also beadvantageously used in rotors of narrower width. It will be understoodthat the construction of the ring 124 is similar to that of the ring125', and that the ring 124 p-rovides an imperforate area 124g inopposed relation to the light phase outlets 107.

Preferably, suitable elements, such as perforated rings, are included inthe light `and heavy clarifying Zones of the rotor. For example, asillustrated in FIG. 1, the light phase clarification zone is providedwith a group of perforated concentric -rings 24. The primary purpose ofthe rings 24 is to promote clarification of the light phase, and usuallyat least three such rings will be employed. In the outer portion ofrotor chamber 12 there is provided another group of radially spacedconcentric are similar to rings 24 in that they are provided withaxially and circumferentially distributed perforations. Rings 25 areintended primarily to promote clarification of the heavy phase. Usuallyat least two such rings will be employed, although in certain cases thenumber of heavy phase clarification rings can be further reduced oreliminated altogether. Other types of elements in the clarifying zonescan also be employed, such as the axially-spaced radially-extending discdescribed in Patent 3,053,440.

It will be understood that the present invention does not require theuse of any particular number of rings Within the contacting section ofthe rotor. However, usually at least eight rings, or four pairs ofrings, will be employed. The preferred number of rings in the contactingsection, of course, will depend on the diameter of the rotor, which canrange from 10 to 60 inches in diameter, but will usually be from 20 to50 inches in diameter. The permissible rotational speed will varyinversely with the rotor diameter. For example, speeds up to 5,000r.p.m. can be used with -a 12 inch rotor diameter, while speeds as lowas 1,200 r.p.m. may be preferred for a 60 inch rotor diameter. Withrotors having diameters ranging from 20 to 50 inches, the rotationalspeeds will usually range from 4,000 to 1,600 r.p.m.

The perforations in the opposed plate sections of the contacting ringscan vary in size according to the p-articularl phase systems beingcontacted, the desired ow rates, etc. The pressure drop across the ringperforations should be sufficient to maintain substantiallyuni-directional flow, and thereby avoid any undue channeling of theopposite phase. Usually perforation diameters of from 1/16 to 1A inchcan be used. The radial distance or clearance between the rings in thecontacting section can also vary over a considerable range. Usually,however, the maximum clearance between the rings will not be greaterthan 2 inches, while the minimum clearance will not be less than 1Ainch. With the embodiment of FIG. 1, the ring clearance will vary fromthe entrance port end to the exit port end of the passageways. Usually,the maximum clearance at the exit port end of the passageways will notbe greater than 2 inches, and the minimum clearance at the entrance endof the passageways will not be less than 0.2 inch.

With respect to each individual ring, the two different ow portproviding sections should have radial positions differing by at least0.2 inch and preferably by at least 0.4 inch. With the embodiment ofFIG. 1, these radial distances would apply to the outer ends of therings, while with the embodiment of FIG. 3 the radial distances wouldapply to the perforated plate sections, such as the sections a and10017. The difference in the radial positions of the perforated platesections can be increased over the figures given, but after a certainpoint is reached the increase in stage eiciency within each annularpassageway is offset by the reduction in the total number of passagewayswhich can be included within a given diameter rotor. Usually, thedifference in radial position of the perforated plate sections for eachring will not be greater than l inch.

With devices of the character described herein, a pressure differentialis maintained between the light phase in and the light phase out. Morespecifically, the light phase is pumped to the rotor under a substantialpressure, say 50 to 200 p.s.i., while the light liquid out is removedfrom the rotor at a lower pressure of say, 40 to 180 p.s.i. A backpressure regulator or a throttling valve is employed to maintain thepressure on the light liquid out. The heavy liquid is also pumped intothe rotor under substantial pressure, which usually approximates theback pressure on the light liquid out. While back pressure can bemaintained on the heavy liquid out, usually the heavy liquid isdischarged to the atmosphere with no back pressure being maintained. Theprincipal interfacial boundary between the light and heavy phases withinthe rotor can be controlled by regulating the light liquid out backpressure in relation to the light liquid in pressure. Usually, theuseful range of variation will be where the light liquid out pressure isfrom 30 to 90% of the light liquid in pressure. When the light liquidout pressure is low relative to the light liquid in pressure, theprincipal interface will approach the rotor shaft. When the light liquidout pressure is relatively high compared with the light liquid inpressure, the interfacial boundary will move toward the outer positionof the rotor. However, one of the advantages of rotors constructed inaccordance with the present invention is that the rotor will operatesatisfactorily with the principal interface in varying positions rangingfrom a position within the heavy liquid clarifying sectionu throughpositions within the contacting section, to positions within the lightliquid clarifyingsections. It will be understood, however, that the backpressure on the light liquid out should not be so low that the rotorfloods with the heavy phase, nor should the back pressure be so greatthat the rotor iloods with the light phase.

The contacting apparatus of this invention can be employed in a varietyof applications. For example, the apparatus can be utilized for theextraction of hydrogen peroxide from an oxidized solution ofhydroquinone cornpound into water. It can also be used for the phenol orfurfural extraction of petroleum oils, such as lubricating oils, and forcaustic treatment of gasoline.

While in the foregoing specication this invention has been described inrelation to a number of specific embodiments thereof and many detailshave been set forth for purpose of illustration, it will `be apparent tothose skilled in the art that the invention is susceptible to additionalembodiments, and that many of the details described herein can be variedconsiderably without departing from the basic principles of theinvention.

We claim:

1. In an apparatus for centrifugal contacting of two at least partiallyimmiscible liquid phases of different densities, said apparatus being ofthe kind having a rotor adapted for rotation about a horizontal axis andproviding a cylindrical chamber therein extending radially outward fromsaid axis, the radially innermost and outermost portions of said chamberproviding respectively light and heavy phase clarifying zones and theintermediate portion of said chamber providing a countercurrentcontacting zone,

a group of rings disposed in radially spaced-apart relation Within saidcontacting zone to provide a plurality of annular axially-extendingpassageways therebetween,

each of said rings being provided with at least two perforated platesections for radial phase ow with least a relatively imperforate area ofsaid ring extending therebetween,

i one of said plate sections of each ring being for the flow of theheavier phase to the next outer one of said passageways,

the other of said plate sections being for the flow of the lighter phaseto the next inner one of said passageways,

said one plate sections being positioned in radiallyopposed relation tosaid other plate sections for adjacent rings to provide at least twopairs of opposed plate sections for each of said passageways,

the imperforate areas of adjacent rings also being in radially-opposedrelation,

' one of said pairs of plate sections serving yas phase entrance portsfor each of said passageways and the other pair serving as phase exitports,

within each'of said rings said one plate section being located at agreater radial distance from said axis than said other plate section andthe said imperforate section which extends therebetween being inclinedat an acute angle with respect to the horizontal at the intersection ofthe said imperforate section with an imaginary vertical plane throughthe axis of said rotor,

whereby said phases are forced through the pairs of plate sectionsserving as said entrance ports for thorough intermixing in the portionsof said passageways between said entrance ports, passed co-currentlythrough the portions of the passageways between said imperforate areas,and separated in the portions of the passageways between said exitports.

2. The apparatus combination of claim l wherein said perforated platesections are axially spaced-apart and extend circumferentially aroundsaid rings.

3. The apparatus combination of claim 2 wherein said rings are eachprovided with two of said perforated plate sections with one of saidimperforate areas extending therebetween.

4. The apparatus combination of claim 2 wherein said rings are eachprovided with three of said perforated plate sections with saidimperforate areas extending therebetween.

5. The apparatus combination of claim 1 wherein at two of saidperforated plate sections are located in the axially outer portions ofsaid rings and extend circumferentially therearound.

6. The apparatus combination of claim 1 wherein each of said rings has afrusto-conical shape extending across said rotor, the walls of adjacentrings alternately converging towards opposite sides of said rotor.

7. The apparatus of claim 1 wherein each of said rings is formed from apair of frusto-conical members, the walls of adjacent rings alternatingwith respect to their convergence and divergence toward the center andsides of said rotor.

8. In an apparatus for centrifugal contacting of two at least partiallyimmiscible liquid phases of different den` sities, said apparatus beingof the kind having a rotor adapted for rotation about a horizontal axisand providing a cylindrical chamber therein extending radially outwardfrom said axis, the radially innermost and outermost portions of saidchamber providing respectively light and heavy phase clarifying zonesand the intermediate portion of said chamber providing a countercurrentcontacting zone,

a group of rings disposed in radially spaced-apart relation within saidcontacting zone to provide a plurality of annular axially-extendingpassageways therebetween, said passageways being circumferentially andaxially open and unobstructed to liquid flow,

said rings being formed of at least one frusto-conical member, andproviding wall portions inclined at an acute angle with respect to thehorizontal at the intersections of said wall portions with a verticalplane through the axis of said rotor,

each of said rings being provided with at least two perforated sectionsarranged in axially-spaced relation with a relatively imperforate areaof the ring extending therebetween,

one of said perforated sections being for the iiow of the heavier phaseto the next outer one of said passageways,

the other of said perforated sections being for the flow of the lighterphase to the next inner one of said passageways,

said perforated sections being positioned in radiallyopposed relationfor adjacent rings to provide two pairs of opposed perforated sectionsfor each of said passageways,

the irnperforate areas of adjacent rings also being in radially-opposedrelation,

one of said pairs of sections serving as phase entrance ports for eachof said passageways and the other pair serving as phase exit ports,

said plate sections serving as phase entrance ports being radiallycloser together than the sections serving as said exit ports.

9. The apparatus combination of claim 3 wherein each of said rings isformed from a pair of frusto-conicalpembers, the walls of adjacent ringsalternating with respect to their convergence and divergence toward thecenter and sides of said rotor.

10. In an apparatus for centrifugal contacting of two i at leastpartially immiscible liquid phases of different densities, saidapparatus being of the kind having a rotor adapted for rotation about ahorizontal axis and providing a cylindrical chamber therein extendingradially outward from said axis, the radially innermost and outermostportions of said chamber providing respectively light and heavy phaseclarifying zones and the intermediate portion of said chamber providinga countercrrent contacting Zone,

a group of rings disposed in radially spaced-apart relation within saidcontacting zone to provide a plurality of annular axially-extendingpassageways therebetween, said passageways being circumferentially andaxially open and unobstructed to liquid flow,

said rings having a frusto-conical shape and providing walls inclined atan acute angle with respect to the horizontal at the intersections ofsaid walls with a vertical plane through the axis of said rotor,

the Walls of adjacent rings alternately converging towards oppositesides of said rotor to provide passages therebetween which arerelatively narrow at one end and enlarged toward their opposite end inan alternating pattern from one ring passageway to the next adjacentring passageway,

said rings adjacent their converging end portions providing phaseentrance port means respectively for the light phase and the heavy phaseso that said phases are introduced into the narrow end portion of saidpassageways and pass cocurrently toward the enlarged end portionsthereof, and

phase exit port means provided adjacent the diverging end portions ofsaid rings respectively for the light phase and the heavy phase so thatsaid phases may separate within the enlarged end portions of saidpassageways and ilow therefrom into the restricted end portions of thenext adjacent passageways.

References Cited by the Examiner UNITED STATES PATENTS 12/1951 Nyrop233-15 233-15 2,578,485 3,108,953 10/1963 Palmqvist et al

1. IN AN APPARATUS FOR CENTRIFUGAL CONTACTING OF TWO AT LEAST PARTIALLYIMMISCIBLE LIQUID PHASES OF DIFFERENT DENSITES, SAID APPARATUS BEING OFTHE KIND HAVING A ROTOR ADAPTED FOR ROTATION ABOUT OF THE KIND HAVING AROTOR A CYLINDRICAL CHAMBER THEREIN EXTENDING RADIALLY OUTWARD FROM SAIDAXIS, THE RADIALLY INNERMOST AND OUTERMOST PORTIONS OF SAID CHAMBERPROVIDING RESPECTIVELY LIGHT AND HEAVY PHASE CLARIFYING ZONES AND THEINTERMEDIATE PORTION OF SAID CHAMBER PROVIDING A COUNTERCURRENTCONTACTING ZONE, A GROUP OF RINGS DISPOSED IN RADIALLY SPACED-APARTRELATION WITHIN SAID CONTACTING ZONE TO PROVIDE A PLURALITY OF ANNULARAXIALLY-EXTENDING PASSAGEWAYS THEREBETWEEN, EACH OF SAID RINGS BEINGPROVIDED WITH AT LEAST TWO PERFORATED PLATE SECTIONS FOR RADIAL PHASEFLOW WITH A RELATIVELY IMPERFORATE AREA OF SAID RING EXTENDINGTHEREBETWEEN, ONE OF SAID PLATE SECTIONS OF EACH RING BEING FOR THE FLOWOF THE HEAVIER PHASE TO THE NEXT OUTER ONE OF SAID PASSAGEWAYS, THEOTHER OF SAID PLATE SECTIONS BEING FOR THE FLOW OF THE LIGHTER PHASE TOTHE NEXT INNER ONE OF SAID PASSAGEWAYS, SAID ONE PLATE SECTIONS BEINGPOSITIONED IN RADIALLYOPPOSED RELATION TO SAID OTHER PLATE SECTIONS OFADJACENT RINGS TO PROVIDE AT LEAST TWO PAIRS OF OPPOSED PLATE SECTIONSFOR EACH OF SAID PASSAGEWAYS, THE IMPERFORATE AREAS OF ADJACENT RINGSALSO BEING IN RADIALLY-OPPOSED RELATION, ONE OF SAID PAIRS OF PLATESECTIONS SERVING AS PHASE ENTRANCE PORTS FOR EACH OF SAID PASSAGEWAYSAND THE OTHER PAIR SERVING AS PHASE EXIT PORTS, WITHIN EACH OF SAIDRINGS SAID ONE PLATE SECTION BEING LOCATED AT A GREATER RADIAL DISTANCEFROM SAID AXIS THAN SAID OTHER PLATE SECTION AND THE SAID IMPERFORATESECTION WHICH EXTENDS THEREBETWEEN BEING INCLINED AT AN ACUTE ANGLE WITHRESPECT TO THE HORIZONTAL AT THE INTERSECTION OF THE SAID IMPERFORATESECTION WITH AN IMAGINARY VERTICAL PLANE THROUGH THE AXIS OF SAID ROTOR,WHEREBY SAID PHASES ARE FORCED THROUGH THE PAIRS OF PLATE SECTIONSSERVING AS SAID ENTRANCE PORTS FOR THOROUGH INTERMIXING IN THE PORTIONSOF SAID PASSAGEWAYS BETWEEN SAID ENTRANCE PORTS, PASSED CO-CURRENTLYTHROUGH THE PORTIONS OF THE PASSAGEWAYS BETWEEN SAID IMPERFORATE AREAS,AND SEPARATED IN THE PORTIONS OF THE PASSAGEWAYS BETWEEN SAID EXITPORTS.